The present invention relates to a system for vaporizing liquefied petrol gas heated by engine lubricating oil.
It aims at supplying liquefied petrol gas (L.P.G.) to internal combustion engines normally a receiving liquid fuel.
It is suitable to all types of internal combustion engines, of the carburetor or injection types, whether they are stationary engines, land vehicle engines, or boat engines.
Liquefied petrol gas is increasingly used as a source of energy for motor vehicles. Indeed, this fuel has very interesting advantages, the most important of which are low pollution, and an advantageous taxation practiced by numerous countries and allowing a substantial cost reduction per kilometer.
Using liquefied gas to operate an engine initially designed to receive a liquid fuel requires the use of a special device ensuring the vaporizing of the gas under pressure, and a predetermined throughput.
This device has the shape of a housing, generally made of light cast metal, such as aluminum and comprising a double enclosure formed of a chamber for vaporizing the gas, and of a temperature chamber in which a hot liquid circulates, which is generally constituted by the engine cooling water collected due to a branch provided on the circuit connecting the latter to the radiator. The two chambers have a common wall arranged so as to allow a good transmission of calories.
For certain types of engines, such as air-cooled engines or sea water-cooled marine engines, it is difficult, even impossible, to use the coolant to ensure the provision of calories necessary for the vaporizing of the liquefied gas.
In addition, it takes a fairly long time for the cooling water to reach the necessary temperature for vaporizing the liquefied gas, particularly in cold weather, which requires the use of gasoline during the starting period; such period can last several minutes. Moreover, the energy supply decreases substantially when the engine is idle, frequently forcing the user to switch to the gasoline supply when he is driving in town or is caught in traffic jams.
The Patent Application No. FR 97 01 705, filed by the same inventors, describes a housing for vaporizing the liquefied gas comprising, within the temperature chamber, a heating element constituted of an electric resistance controlled by a thermostat and connected to the engine electric circuit or to an external source, the temperature chamber preferably being filled with a good heat conducting liquid or pasty product that is capable of transmitting the calories of the hot liquid to the vaporizing chamber.
The tests conducted with this device have shown that it is very difficult, using this means, to produce a sufficient amount of energy with a conventional vaporizing housing and that to function properly, it is necessary to use an oversized apparatus and a more powerful source of current than that which is usually found on common vehicles.
The device according to the present invention eliminates all these drawbacks. Indeed, it makes it possible to very quickly put the liquefied gas supply into operation when starting, with a conventional housing; it can operate correctly even when the engine is running at very low speed, and can be used with all types of oil circulation lubricated internal combustion engines, regardless of its cooling system. Furthermore, it plays the role of an oil radiator, and can allow suppressing this device in certain cases.
It is constituted of a housing for vaporizing the liquefied gas, whose temperature chamber is branch-connected, by a double conduit, to the engine lubricating circuit, by means of a connecting block mounted at the oil filter base and normally used by certain engines for radiators cooling the lubricating fluid.